1. Field of the Invention
The present invention relates to a digital signal transmission system having monitor equipment.
The recent rapid progress in the field of a communication technique greatly relies upon a digital transmission system that operates to transmit digital signals, such as telephone signals, a variety of data signals and so on, under a time division multiplex mode. Therefore, there is a strong demand for a reliable monitor of a related digital signal transmission system. That is, it is necessary to determine if fault occurs in the digital signal transmission system, the location of the fault therein and further to restore the related faulty portion quickly and correctly.
The present invention therefore provides a digital signal transmission system having monitor equipment that can easily achieve the monitor.
As will be explained later, the digital signal transmission system is comprised of, as major parts, a serial/parallel converter and a parallel/serial converter, which play an important role when the digital signal transmission system is incorporated into a socalled highway transmission line, to increase the transmission efficiency of the signals, i.e., an increase in the transmission speed and provision of an economical facility, and thus the converters are essential for a highway transmission line. This being so, it is very effective to monitor these converters per se to improve the maintenance of the highway transmission line and also reliability thereof.
2. Description of the Related Art
Conventionally, the digital signal transmission system is monitored by the use of a well known parity check and a pass pattern check, which will be explained hereinafter.
However, in the conventional digital signal transmission system having monitor equipment there are the following problems.
(1) it is difficult for the monitor equipment to achieve a monitor of the aforesaid serial/parallel (S/P) and parallel/serial (P/S) converters per se, and PA1 (2) much hardware is required for constructing the monitor equipment in the digital signal transmission system. In actuality, there has been no practical monitor equipment that can monitor the inside of each of said S/P and P/S converters.